Telephone system



' Jun. 23, 1940. E. s. PE'i'ERSOLI 2,187,951,

TELEPHONE SYSTEM Filed Jan. 6, 1958 4 Sheets-Sheet 1 INVENTOR. ED WA RD S. PETERSON B M M ATTORNEY;

Jan. 23, 1940. E. s. PETERSON 2,137,951 I TELEPHONE SYSTEM Filed Jan. 6, 1938 4 Sheets-Sheet 3 Nmmu 3, +96,

INVENTOR. V EDWAR D S. PETERSON M,%

sem

ATTORNEYS.

Patented Jan. 23, 1940 PATENT TELEPHONE SYSTEM Edward S.- Peterson, Elmwood Park, Ill., assignor to Associated Electric Laboratories, Inc., Chicago, Ill., a c'orporation of Delaware Application January 6, 1938, Serial No. 183,591

41'Claims.' (Cl. 179-31) The present invention relates to telephone systems and. has for one of its objects the provision of improvements in small automatic telephone systems adapted for use in providing intercar communication facilities between the various cars of a train or the like.

Systems suitable for the purpose specified conventionally comprise a plurality oftelephone stations conveniently located in the various cars of the train, and a line comprising a plurality of talking conductors interconnecting the'various stations. The utility of such a system resides primarily in the provision of facilities whereby passengers or porters may converse'with the dining car and club car attendants for the purpose of placing orders for food and drink and for requesting other services. Obviously, there is no utility in providing such facilities for calls of a social nature. Moreover, the cost of providing a system for the purpose indicated and designed to handle more than one call at a time, would be prohibitive. It is highly desirable, therefore, to prevent the apparatus of the system from being used in connection'with social calls since, otherwise, it might be tiedup for extended periods of time by thoughtless passengers and to the inconvenience and disturbance of other passengers. Since ordinary conversations of a business nature are of short duration, one line interconnecting the several telephone stations is more than adequate for the provision of reasonably good service. With only one line available, however, the provision of suitable apparatus for preventing the line from being seized by a calling station when it is already busy becomes a practical necessity. For similar reasons, it is desirable to so arrange the system that dial tone indicating an idle condition of the line is given to a calling party when the line is in fact idle.

It is an object of the present invention, therefore, to provide an improved telephone system of the character briefly outlined above whichis of economical and flexible arrangement, is positive and reliable in its operation even under the most adverse operating conditions, and is so arranged as to prevent connections from being established to certain of the telephone stations when calls being initiated when the line is engaged in a pre viously established connection;

It is a still further object of the to provide in a telephone system of the character described, animproved and exceedingly simple arrangement for automatically giving an audi- OFFICE invention ble signal to. a calling party when the line is idle and when the calling party initiates a call from one station to a second station. I

In the illustrated embodiment of the present invention, each of the plurality of telephone sta tions associated with the line comprises a tele phone, an impulsing device, and a signal device and has associated therewith automatic, station selecting, switching apparatus of the impulse responsive type. Commonly associated with all of the stations is a dial tone source in the form of an undulating voltage generator connected to impress its output voltage between the talking conductors of the line. In accordancewith'one feature of the invention, a device in the form of a relay operativein response'to the initiation of a call at one of the stations is provided for con-' ditioning all of the automatic switches to respond to the operation of the impulsing device,

at. the calling station and for rendering all of operative to initiate the operation of the dial.

This relay further functions tone generator, whereby an audible indicationis given to the calling party that the line is idle."

The switching apparatus associated with each of the telephone stations includes an automatic switch having operating positions individually corresponding to the various telephone stations, and further includes control apparatus responprovided at a calling station for causing the switch to operate to a desired position corre-.

sive to the operation of the impulsing device spondi'ng to a called station. Following the op;-

eration of the switches to a position corresponding to a particular called station, the switch at this station functions to complete a circuit for energizing the signal device thereat, and also to connect the telephone at this station across the talking conductors of the line. A further feature of the invention is directed to the provision of a device which responds to the first pulse trans- In accordance with a further feature of the invention, the system is so arranged that calls initiated at certain of the stations, such, for example, as those provided in the sleeping cars, may only be extended to predetermined ones of the other stations, as, for example, those provided in the club and dining cars, whereas calls initiated at the stations provided in the dining and club. cars may be extended to any of the other stations in the system. To this end, the

switches associated with the stations arranged for limited call service each have a predeterticularity in the appended claims.

mined operating position intermediate the home position and certain of the operating positions I individually corresponding to the other stations.

Also provided in individual association with the stations of this character is apparatus which re sponds to the operation of the associated switches to the predetermined operating position mentioned above to render all of the automatic switches non-responsive to further operation of the impulsing deviceprovided at the associated station. By this arrangement, it is possible for a connection successfully to be completed between a station of the form noted and any station corresponding to an operating position of the switches intermediate the home position thereof and the predetermined operating position noted. All of the other stations, namely, those individually corresponding to the operat ing positions of the switches succeeding the predetermined switch operating position, cannot be reached when calls are initiated thereto from the stations arranged for limited call service.

Further features of the invention pertain to the particular arrangement of the circuit elements whereby the above-described services are attained.

The novel features believed to be characteristic of the invention are set forth with par- The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by paratus illustrated in Fig. 1; Fig. 3 diagrammatically illustrates the apparatus provided in two additional sleeping cars and. the dining car of the train and also the substation apparatus provided at a station located in the club car of the train; and Fig. 4 illustrates the automatic switching equipment provided in the club car in association with the substation apparatus illustrated in Fig. 3, and also the equipment commonly associated with all of the telephone stations.

Referring now to the drawings, there is illustrated a telephone system for use on a Pullman train and comprising a plurality of telephone stations A, B, C, D, E, and F interconnected by a line 287, which line comprises a pair of talking conductors C285 and C284 and a common or control conductor C285. The enumerated stations are located in different cars of the train, and the line 281 is divided into sections individually extending throughout the length of the several cars which are provided with telephone facilities.

More specifically, the stations A and B are both located in one of the sleeping cars, the station C is located in a second sleeping car, the station D is located in the dining car, the station E in a third sleeping car, and the station F in the club car. The various line sections of the line 281 interconnecting these two stations are in dicated as being connected by the sets of terminals 3, 312, 3l3 and 3, respectively. The line further comprises a fourth conductor divided into section C2|8, CZIB', etc., individually extending through the cars equipped for telephone service and joined together at the terminals 3I5,

of the sleeping cars, aside from the first, is indicated as having embodied therein a single station, it is pointed out that each compartment ofeach sleeping car may be equipped with an outlet jack by way of which a portable telephone may be connected to have access to the line. Thus, the station B in reality consists of an outlet jack I adapted to accommodate the terminals of a multicontact plug M8 and having its contacts connected by way of the conductors forming a cable 288 to the switching apparatus provided in the car so that the portable telephone substation equipment may be connected to have access to the line 281. Additional outlet jacks individually located in the various other compartments of the sleeping car in which the station A is located may be provided, in which case the corresponding contacts of the several jacks are multipled together.

The same equipment is provided at each of the telephone stations, that at the station A being illustrated as comprising a telephone hand set 555 including a receiver I60 and a transmitter I65, a dial actuated impulsing device I10, a

signal device in the form of a buzzer I85, and a hook or cradle switch lBll located intermediate the cradle arms of the supporting member for the hand set I55 in the usual manner. Similarly, the apparatus provided at the station F comprises a hand set 36!] including a transmitter 365 and a receiver 370, a dial actuated impulsing device 390, a signal device in the form of a buzzer 385, and a hook switch 380. Likewise the portable equipment illustrated as being located at the station B comprises a hand set Hill, a dial actuated impulsing device I39, a signal device' H5, and a hook switch I20.

Each of the transmitters and receivers embodied in the various hand sets may beof any standard commercial construction and for this reason these elements have been only schematically illustrated in the drawings. It is pointed out, however, that each of the'transmitters I05, I55, 365, etc., is preferably of the self-powered type, such that the necessity of using an auxiliary current source for voice frequency current transmission is obviated. Several well-known transmitters of this type are commercially available. In brief, a transmitter of this form usually comprises a diaphragm which is connected by means of a sturdy but very light connecting rod i to an armature balanced between the poles of an extremely powerful permanent magnet. In its operation and when sound waves impinge upon the diaphragm, the diaphragm vibrates in accordance with these waves to transmit the vibrations to the armature. The armature, in turn, vibrates and sets up variations in the magnetic lines of force, both in number and direction,

causing an induced alternating voltage to be developed in the coil windings forming a part of 3H6, 3H, and M8, as indicated. Although each generated varies in amplitude and frequency in accordance with the amplitude an'd'intensity of the input sound waves.

Associated with each of the telephone stations is an automatic station selecting switch of the impulse responsive type, those providedin association with the stations A and F being illustrated generally at 260 and 440,- respectively. Normally, each of the twoenumerated switches is arranged to be operatively associated only with the indicated stationsA and F, respectively. For

the purpose of rendering the switch 260 available to the use of a portable telephone located at one of the compartment stations, as, for example, the station B, there is provided a relay R250 which is arranged to alter the circuit connections, in the manner pointed out in detail hereinafter, so that this switch may be controlled sociated with the bankcontact setsin the order of their enumeration, and means comprising a motor magnet 26'! and a ratchet and pawl mech- 1 anism, not shown, for advancing the wipers from the home position of the switch, as illustrated in the drawings, to any one of a plurality of operating positions. Similarly, the automatic switch 440 comprises three sets of bank contacts I,

. 442'and 443, wipers 444, 445 and 446 respectively associated with the bank contact sets in the order named, and means comprising a motor magnet 441 and a ratchet and pawl mechanism, not shown, for advancing the wipers from the home position of the switch, as illustr'ated in the drawings, to any one of a plurality of ofinormal" or operating positions, As pointed out more particularly hereinafter, certain of the plurality of oif-normal or operating positions of the respective switches individually correspond to particular ones of the telephone stations and,

thus, these switches are arranged to function as station selecting apparatus.

The control apparatus incorporated in or associated with each of the automatic switches provided in the respective sleeping cars may be identical with that illustrated in. Fig. 2 in association with the station A, the extension station B, and any other extension stations located in the same car. In brief, the control apparatus 11- lustrated in Fig. 2 comprises a relay R230 which is operative in response to theinitiation of a call at the station A to condition all .of the auto-.

matic switches embodied in the system to respond to the operation of the impulsing device H provided at the station -A.' More specifically, this relay is operative to. prepare a series impulsing circuit including the windings of all of the impulsing relays R240, R330, R340, R350, R430, etc., the springs I'll of the impulsingdevice I10, the winding of R480, and the various sections of the line conductor .C2l8, whereby each of the enumerated pulsing relays is energized and deenergiz ed during each'impuls'e dialed atthe station A. This relay, namely R230, is further operative to connect the elements of thetel ephone hand set I55 across the talking conductorsC284 and C286 of the line 281.v In orderto render the various automatic switches of the system nonresponsive to the operation of the impulsing devices provided, respectively, at the stations other ciated stations. Since thesefcorresponding relays are rendered inoperative following operation of R230, it willbe apparent that the last-named relay also functions as a device for preventing the telephones atthe otheristations from being -con nected across the talking conductors of the line in response to the initiation of calls at the said other stations. The automatic switching apparatus associated with thestation A further'comprises the pulsing relay R240, a slow to-release hold relay R220, a call limiting relay R2! and a slow-to-release line switching and buzzer control relay R2'0l).

The automatic switching apparatus associated with the telephone stations and E and provided, respectively, in'the second and third sleeping cars may be identicalwith that just described. The automatic switching apparatus provided in the dining car and associated with the telephone station D difiers from that embodied in the respective sleeping cars in that no control apparatus and more particularly no relay corresponding'to R2lil, is included therein for limiting the stations which-may be called from i the station D. Specifically, the switching apparatus located "in the dining car is identical with that illustrated in Figs. 3 and. 4 and located in the club car.

Briefly described, the' last-mentioned apparatus comprises, in addition to the automatic switch 440 and itsassociated line relay R439, aslow-to-release hold. relay'RMU and a line switching and buzzer control relay'R lilfl. The

apparatusin this car further comprises a relay ".4

R420 which corresponds to the relay R230 provided in the first sleeping car and is operative to perform thesame functions as are set forth above-in the description pertaining to R238.

- The various telephone stations have commonly associated therewith the common equipment 4513 enclosed within the dotted area illustrated in Fig. 4. This equipment comprises a dial tone source or undulating voltagegenerator in the form of a self-controlled relay R lfifi connected to impress its output Voltage by way of condensers 462 and 484. between the two talking conductors C286 and C234 of the line 287.. For the purpose of initiating the operation of this generator, the relay R480 is provided, which relay includes a winding normally included in the above-mew tioned impulsing circuit by way of which the various line relays are energized. This circuit is completed through the operation of a slowtooperate relay R463 which responds to the operation of a common start relay R496. The lastnamed relay is arranged tobe energized in series with'any one of the relays REG/R4320, etc., in

iii)

response to the initiation of a call at any one of the stations respectively associated with the latter relays. The arrangement is such that the operation of the dial tonetvoltage generator is arrested when the first impulse is dialed at any calling station. To this end, there 'is also included in the common equipment 450 a slow-acting relay R410 which is arranged to be controlled by the start relay R49iiland which functions to cause the restoration of R480; the first time the completed impulsing circuit opened at the impulsing device of a calling station. For thepurpose of insuringthe release of the various automatic switches following the operation thereof to complete a desired'connection, thereare provided two additional relays R486and R495.

Current for energizing the various relays, :the signal devices and the operating magnets embodied in the switching apparatus respectively associated with the several telephone stations .is obtained from a common source which preferably comprises'the-storage battery conventionally embodied as standard equipment in the locomotive of the train. This sourceis usually connected to bus conductors which extend throughout the several cars of the train to supply current to the various lighting circuits and other auxiliary equipment. In order to facilitate a description of the circuits involved in the telephone system, the current source has not been illustrated in the drawings, but it is explained that the positive terminal of the source is connectedto all circuit conductors indicated as terminating at ground, whereas the negative terminal of the source isconnected to the various negativeterminals illustrated in the drawings.

Considering new the operation of the system and assuming, for-example, that acall is initiated at the station A located in the first sleeping car to the station F located in the club car, the automatic switching apparatus is conditioned for operation through the removal of the-hand set I55 from its supporting cradlein the usual manner. When this operation is performed, the cradle switch I is caused to operate to its offvnormal position. Assuming that the line is idle atthe time the call is initiated, the operation of the cradle switch I89 results in the completion of a circuit for energizing the lower winding of R23". and the winding of R459 in series, this circuit extending from ground as applied to the conductor C185 by \vayoi the switch springs lad, C275, the lower winding of R233, C285, RAMZ and through the winding of R496 to battery. The relay R238, upon'operating, completes, at

-RA235,v a holding circuit for itself, this circuit extending from grcundas applied'to C185 by way of the switch springs H32 and 483,-,0214, RA235 and through the upper winding'of R230 to battery. The relay R23i3 is so constructed that it closes the contacts associated with RA23-5 to complete the above-traced holding circuit for itself before the contacts associated withRAZSB are closed. When the last-mentioned contacts are moved into engagement, the'lower winding of R238 is short-circuited so that ground as extended to C215 is directly applied to the control conductor C285, thus removing from this conductorthe predetermined potential, namely, battery potential, necessary to the energization of the relays corresponding to R239 and located in the other cars.

At RAZSI, the relay R230 prepares a circuit, traced hereinafter, for energizing R215 and, at RAB-i, it opens a point in the path normally short-circuiting the springs ill of the irnpulsing device ill), thereby to render this device effective to control the pulsing reiays correspondi-ng to and including Rf lii. At RA233, the'relay R230 completes a path for connecting the transmitter and receiver of the telephone hand set E55 across the tailing conductors C235 and C286 of the line 281, this path extending from the conductor C285 by way of the conductor C2113, the transmitter 165 andthe receiver H50 in parallel, CHI and RA233 to the oppositetalking conductorC284.

The startrelay R490 operates, when energized in series with the lower winding of R230, and is held operated following the operation of R230 through the application of ground potential directly'to the control conductor C285. At RA492 and RC493, the relay R490 completes-an obvious circuit for energizing the slowto-operate relay B 163, which latter relay operates, after an ine terval, to complete at RAdSEiand RA lfifi a path for short-circuiting the winding of R486 from ground on C285. At RAQSS, the relay R463 short circuits the armature RAM? to hold the start relay R495 operated after the slow-acting relay R tlll operates. At .RAAGL-the relay R453 completes an obvious .circuit for energizing 3495, Which-latter relay operates to complete, at RA495 and R0438 an obvious circuit for energizing R416. The relay R 510 now operates to prepare, at RAM i ,,.apath forshort-circuiting the winding. of R; to open. at BAA'IZ, a-poi-nt in the original operating circuit for R490; and to prepare, ,at RAA'HE, 'a holding circuit for itself. At RAM", the .relay R 590 prepares the above-mentioned impulsing circuitby way of which all of the line relays ,-.are energized in series. This circuit is completed atRA lM when R463 operatesand is arranged to be controlled by the impulsing device Ill] provided at the calling stationand includes the winding of R638. More specifically, this cir cuit. extendsfrom ground as applied toCii35 by wayof Cl-St, the impulsing springs Hi, C213, RAQEil, the-winding of R230, C2l8, the windings $3.339, REM-and R350 in series, C2l8', RAGZZ, the winding-of R430, B51464, RA iill, the winding of :RAGELand through theresistor 1385 to battery. Theconductor C585 is shown. in dotted lines for the purposeof .denotingqa non-permanent connection. This conductor is in reality a jumper wire which is connected between'ground and one of the impulsing springs. of the dialing deviceprovided at the permanent telephone station in the end car of the train of cars equipped for telephone service. The dotted portions of the conductorsleading to the respective relays R33 1, R345! and R350 indicate that these conductors may-be interrupted and include thereinthe con.- tact springs of certain control relays, not shown. All of the -enumerated line relays R240, R330, 123%,.13350 and R430 operate when the abovetraced circuit is contemplated, to condition their respective associated switches to respond .tothe operation of the impulsing device. llll provided at the calling station. The relay RM?) also operates, when energized over. the above-traced circuit and before. the-operation oiRt-Hl, to open, atRAtiil,

a point-in the path traced hereinafter for shortcircuiting itsown winding andto complete, at RA482, a circuit for initiating the 'operationcf the. relay Refill which forms the dial tone voltage generator. This last-mentioned circuit extends from ground at RA482 by way of the lower winding of R460 to battery. I

When R468 operates, it completes, at RA i'tl,

an obvious path for connecting its upper and lower'win'dings in series. These two windings are an audible indication isgiven to thevcalling party that the line is idle. 1

When the line relay associatedtwithethe' switching relay R200. and the operatingmagnet 261 in parallel. -In-a similar. manner, thehold relays provided in the switching equipment assooiated with the stations. C, D, E and F arecaused to operate. Thus, when .3430, provided as an element of the switching apparatus located in the club car, operates, it completes, at RA43I and RC 433, an obvious circuit for energizing" the hold relay R4l0. LSince the clubcar station is one of the stations arranged for unlimited call service, or arranged so that calls may successfully be completed toany. of .the other stations in the system, no .relaycorresponding to R2) is;provided'.' Hence, the only function of j R41 is to prepare, at RAM! and RC4I4, a point in the circuit, traced hereinafter, for energizing the switching relay R400 and the operating magnet 44'!- in parallel. Since the-apparatus located in the car in association with the station. D is also arranged for unlimited call service .and is in all respects identical to that illustrated in Fig. .fl, the hold relay-fincluded in this apparatus performs only functions corresponding to those performed by R4l0. With the apparatus in this condition, all of theautomatic switches are 0on5 diti'oned to respond to the operation 'of the im pulsing device I provided at the callihgstation. This 0 device isnowoperated to transmit a plurality of impulses. 'for causing the automatic switches to be driven to the operating p0 sition corresponding to the called station F.

More specifically, each timethel impulse springs ill are interrupted, the above-traced pulsing circuit, over which all of the line. relays and R480 are energized, is interrupted. The. resulting operation of the switching apparatusqillua trated in Fig. 2 may be considered as exemplary of the operation of the other similar apparatus provided in the other sleeping cars, and for this reason, the operation of this apparatus will alone be considered in detail. Each time R240 restores, it completes, .at RAM] and RC242, the above-v mentioned circuit' for. energizing R200ja nd the operating magnet 26'! in parallel. This circuit extends from ground at RA24I byjwayof R0242 and RA2Z2 to R0224, where it divides, one branch extending by way of the winding'of R200 to battery, and the other branch extending byway of C2 l5 .andthe Windingof the magnet 20'! to bat? tery. response to its energization. over the above-traced circuit, R200 operates to open, at RA2J4 a point in the path, traced hereinafter, forconnecting the telephone hand set l55 across the talking conductors of the line, and to prepare, at RAZUI and R0203, a point in the circuit,

' traced hereinafter, for energizing R2l0. Due ltO itsslow tmrelease characteristic, the relay'R20li remains operated for the duration of the; series 'of'impulses transmitted from the impulsing dei-, vice HEL For the same reason, the relay R220 is held operated during impulsingh Each time theoperating magnet 25'! is energized and deenergized, it functions in cooperation with its .step,,,s o thatv at.;.the.-.conclusion-of the dialing operation, these wipers stand in the operating position corresponding to they number of impulses making-up'the'fdialednumben' In the present I assumed case; ,the particular operating position of the. switches corresponding to the called station isthe secondofi-normal position, as will be apparent from the wiring arrangement of the bank contact set idiiembodied in the switch 440.: At the, conclusion of the. dialing operation, there:

fore,' thelvilipers .of the'switch 260 remain stand ing in engagement-with the respective third contacts' [of their respective associated contact sets.

Since, all of the switches in the system and cor-f responding to... the switch260 are, operated fin synchronism during the dialing operation, it will bejgap'parent that all Iof'lthese switches will "be" caused to assume the operating position correspending to, the called station. Thus, when R430.

restores'during; the first impulse dialed at the. eallingstation, it completes, at 'RA i-ti ,an'd" R0432 andLRAMZ to RCMQ, where it divides, one

branch extending way of the winding 017E400 way of. C.4|5 and the windingof the magnet 441 to battery. relay R400now operates to per- 30 form functions correspondingtp those performed .tofbatteryg, and .the Iother'branch extending. by

by R200, that.is,,to Open, at'RA404, 9. point in the path, traced below,-Ifor connecting the tele phone handset 3 60v acrossthetalking conductors i I of the line and to "open, at RA40I, a point in the operating circuit .for thejbuzzer 3 85. Thetwo relays 34001 and R41! 0". remain energized throughout thejin pulsingjoperation due to their slowto release,characteristics.1,Since the operating magnet is. energized iand deenergized once duringeach impulse dialed. at the calling 'sta tion, jthewipers 144,. 4.45 and 4 46' of the switch 440 are caused to be advanced to the oiT-normal impulsesmaking up the dialed series. In the presentas'sumed case .Wherein the station F is the called station, these wipers are brought to rest position. which corresponds .to the number of in engagement with the respective third contacts I of.;.their respctive associated sets.v When the I dialing operation is concluded, the springs I'll, of the impulsing device H0 remain closedv to hold of theimpulsing circuit.

, 'Before-.-describing the operation of the switchin'g apparatus providedinthe club car to complete. a connection to the called station vF, 'it is pointed out that the operation 'of the relay R450 which, functions as a dial tone current source, is

opens, at RA482,,the previously traced circuit for energizing the lower winding of R460, there-,

' by to stop the buzzer-like operation of the latter relay. At RA483, the relay R680, upon restor ing, opens a point in the dial tone current path and clearsthe line of allimpedances whichmight interfere with "the transmission of voice free to I operated all of the line relays energized by way 1 $30 I Rl i'hrestoresto .completaat RAMI, a path in-I eluding RAM! for short-circuiting its own Wind'- 1 ing. As thusshort-circuited, no further operation of R430 can occur until R410 is restored." The lastrnentioned relay is, however, held operated throughout the duration of the calland until the line is cleared. When R480 restores, it

. quency' currents over the talking conductors of the line.

Continuing now with the operation of the apparatus illustrated in Fig: 4, shortly after the conclusion of the series of impulses transmitted from the impulsing' device I10 andlwith the wipers of the switch 440. standing in the second oii-no'rmal position, a circuit is completed. for

-. energizing the signal device 335 provided at. the

2t 3 wiper'446, the third contact of the set 44s, (3435,

With the wipers of the switch 440 standing in the second operating positionand when R403 restores, a path is completed for connecting the transmitter 365 and thereceiver 310' of the hand set 350 across the talking conductors C234 and C286 of the line 281. This pathextends from the conductor C284 by way of RA404, the switch and the receiver 310 and transmitter-305 in parallel to the opposite talking conductor C206. The talking loop between the calling and-called stations is thus completed.

" It is pointed out that the second oif-normal or operating position ofthelvarious rotary switches corresponds only to thestation F and, hence, the signal device 385-is the only one energized, and the telephone hand set-360is the. only hand set, other than that provided at the calling station, which is connected tothe talking conductors of the line. To this end the respective third 40 contacts of the two contact sets 442 and 443 are the only contacts of these setswhich. are wired,

the remaining contacts of these sets, which instation F being left dead. The respective third dividually correspond to stations other than the contacts in the contact sets, corresponding to the sets 442 and 443 and included in the other rotary switches, are also left dead or unwired. It-is for this reasonthat the signal device 385 is theonly device. of its kindwhich is energized and the telephone hand set 360 isthe only hand set connected to the talking conductors of the line following operation of the switches to the second operating position. Had. a digit compris in'g one or three impulses been dialed at the station A, a different station would have been signaled following the dialing operation, and the telephone hand set at this: different station would alone have been connected across the talking conductors of the line. v v

When the call is answered at ,the station F through the removal of the hand set 350 from its supporting cradle in the usual manner, the'cradle switch 383 is caused to operate to its off-normal position. As a consequence, the springs 38! and 382 are opened to interrupt a point in the abovetraced circuit for energizing the signal device 385, the springs 382 and 383 are closed, and the springs 334 are closed. From the preceding description, it will be remembered that, ordinarily,

closure of the springs 334 would result in the energization of R420. Due'to the previous operation of R230, however, ground is present on the; control conductor C285, so that the extension of ground from C392 to C439 occasioned by closure of the springs 384, only results in the short-circuiting of the lower winding of R420. Hence, this relay remains deenergized.

No "further operation of 1 the switching apparatus occurs'until such time asthe connection is cleared" out at the calling station. Thus, if the handset. 3601s returned to its cradle before the calling'party hangs up, the only result is a recompletion of the circuit for energizing the signal device 385, all of the switches being held operated. When thehand set I55 at the calling station isthereafter replaced; in its cradle, the holding circuit for R230 is interrupted at the switch springs I82 and 183, and ground is re R490 to battery. The relay R465- operates when energized over this circuit and interrupts at RA481 the circuit holding R463 operated. The relay 453, upon restoring, opens, at RA464, a point in the impulsing circuit and, at RA465 and B14435, points in the series circuit including R435 and R400. AtRA45I, the relay R463 opens the operating circuit for'R495. With R495 deenergized, the weighted armature RA496 is released and starts vibrating alternately to makecontact with its associated contacts R049! and R0498. Due to the slow-to-release characteristic of R410, thisrelay stays operated so long as RA496 engages either of its two associated contacts. When, however, the amplitude of vibration of RA493 dies down so that it no longer engages either of its two associated contacts, R415] restores'to open at R'A4'H thepath short-circuiting the winding of R480 and to reprepare, at RA412, the circuit for energizing R490. When R490 falls back simultaneously with the restoration of R486 at opens, at RAM", a point in the series impulsing circuit. over which all of the line relays are held operated and, at RA492, a further point in the operating circuit for R463;

When the various line relays fall back, the operating circuits for the respective associated hold relays are opened and circuits are prepared for energizing the various operating magnets embodied in the respective automatic switches to cause the wipers of the switches to be driven to the home position. Thus,,when R240 restores,

it prepares, at RAM! and RC242, a circuit for energizing the magnet 26! by way of the circuitinterrupting contacts associated with the armature 261. At RA24I and R0243, the relay R240 interrupts the operating circuit for R220. The

last-mentioned relay restores, after an interval,

energized to drive the wipers 264, 265 and 266 of the switch 260 until they reach the home position of the switch. Since the first contact of the set i is not multipled to the remaining-contacts of this set, the above-traced circuit for energizing the magnet 26! is opened when the wiper 264 is stepped into engagement with its first contact. Thus, the switching apparatus associated with the station A is restored to normal and is in readiness for further use.

,The operations which occur in the restoration to normal of the switching apparatus provided in association with each of the other stations are quite similar to those just described in connection with the apparatus illustrated in Fig. 2. Thus, when the line relay R430 incorporated in the switching apparatus associated with the station F restores, it opens,at RA43I and RC433, the operating circuit for R4I0 and prepares, at RA43I and R0432 a circuit for energizing the operating magnet 441 of the switch 440. This circuit is completed when R4I0 restores and extends from ground at RA43I by way of RC432,

RA HZ, RC4I3, C406, the wiper 444, the multipled contacts of the set 44I the armature 441' and the winding of the magnet 441 to battery. Due to the circuit-interrupting operation of the contacts associated with the armature 441', the operating magnet 44! is repeatedly energized and de-energized to drive the wipers of the switch 440 to the home position, or into engagement with the respective first contacts of their respective associated sets. Obviously, when this position is reached, the operating circuit for the magnet 441 is opened at the wiper 444 and its associated first contact.

If the calling party of the station A hangs up before the called party at the station F replaces his receiver in its cradle, the operated switches are automatically restored to normal in a manner similar to that just described. This is true even though ground as applied to C392 is extended by way of the switch springs 384 to C430 so long as the cradle switch 380 is operated to its oiT-normal position. Thus, when the handset I55 is replaced in its cradle to cause'the restoration of R230 ground is removed from the control conductor C285 so that a circuit is completed for energizing the lower winding of R420 in series with the winding of R490 and in parallel with -R486. This circuit extends from ground on C439 by way of the lower winding of R420 to C285 where it divides, one branch extending by way of RA456 and the winding of R490 to battery and the other branch by way of the winding of R486 and RA465 to ground. Due to the relatively low resistance of the winding of R486, as compared to that of the lower winding of R420, the relay R420 does not operate when energized in parallel with R488.

' eration of R486, the operating circuit for the start relay R490 is open at two points, namely, RA466 and RA412, and can not be completed in response to the initiation of a call at one of the stations'until such time as R410 restores.

The purpose of the arrangement described immediately above is to give the automatic switches sufficient time to restore completely to normal before they are conditioned to respond to impulses transmitted thereto during another call. More particularly, R486 operates when the calling party hangs up irrespective of whetheror not a call is waiting to take the line.. .When R486 operates, R400 restores and, hence, the operating circuit for R490 and the impulsing circuit must be held open until R410 restores. Due to the continued energization of R410 occasioned by the vibration of RA486, however, R410 is held operated for a sufiicient time interval to insure the full release of each of the automatic switches. Thereis. thus eliminated any possibility of the automatic switches being started from an E- The relay R486, however, operates to open the operating circuit for R463,

normal position in response to-the operation of an impulsing device provided at one of the stations.

As indicated above,;the circuit arrangement of the switching apparatus is such that a call can only be initiated when the line 281 is idle. Thus,.

if the line 281' is busy at the time the call is initiated at the station A, the lower winding of R230, instead of being energized when the cradle switch I80 is operated to the off-normal position, is short-circuited. The short-circuiting path extends from ground at CI85 by way of the switch springs I 84, C215 and'the lower winding of R230 back to ground asapplied to the control conductor C285. Hence, 'R230'remains deenergized, no dial tone is received by the calling party, and the calling party is informed by the absence of such. tone that the line is busy. Since, under the conditions stated, R230 does not operate, it is obvious that the attempted initiation of the call in no way interferes with the previously established connection responsible for the busy condition of'the line.

As pointed out previously, when a plug terminating a portable telephone set is inserted in one of the extension jacks provided in the first sleeping car, the automatic switching equipment illustrated in Fig. 2 is conditioned to complete a connection to the telephone station thus formed or to respond to the operation of the equipment providedat the station to extend a connection to a desired called station. When, for example, the plug I48 terminating the port able telephone is inserted in the jack I40, the relay R250 is conditioned to operate to rearrange the circuit connnections sothat the impulse retion, a circuit is completed for energizing R200,

this circuit extending from ground as applied to the jack spring I 53 by way of the plug spring I41, the switch springs N4, the plug spring M2, the jack spring I40, C282and through thewinding of R250 to battery. The relay R250,.upon operating,

completes, at RA253, acircuit for energizing the lower Winding of R230 in series with the start -relay R490, this circuit being similar to that traced previously but difiering therefrom in that it starts from ground at RA253, rather than from ground as applied to"CI85. At RA252, the relay R250 prepares a holding circ'uit for R230, this circuit being completed upon the operation of R230 and extending from ground at RAZEZ by way of RAZSE: and the upper winding of R230 to battery. At RA25I, the relay R250 opens a point in the path normally" provided for short-circuiting the impulsing springs I3I of the impulsing device I30. At RA254, and R0250, the relay R250 prepares a point in'the path for-connectingthe transmitter and receiver of the hand set 500 across the talking conductors of the line 281' RAMA" and R0256 to the opposite talking conductorCEBB. The operation of R230 also results in the connection of the hand set 855 across the talking conductors of the line 28'! in the manner described previously. At RA235, the relay R233 completes a path for' extending ground from RAESS directly to the control conductor C285, thereby to render the rotary switches, other than the switch 2%, non-responsive to the operation of the impulsing devices respectively provided at all of the stations other than the stations A and B.

When the start relay R498 operates, following its energization in series with the lower winding of R238, it performs the functions described above, that is, it causes dial tone current to be transmitted through the receiver at the calling station B and completes the series impulsing circuit in which are energized. the various line relays associated, respectively, with the several automatic switches. In thiscase, however, the impulsing circuit is arranged to be controlled by the impulsing devicev I39. Thus, the circuit now extends from ground as applied to Cl85 by way ofClliS, 0272, the switch springs lH, C213, C288, the plug and jack springs I5I and HM, the impulsing springs lti, the plug and jack springs M6 and C2l9, the series'connected windings of am, R330, Rt lfi, Rtfiii and R536, RAMA, RA lill, the winding of PAM! and through the resistor 385 to battery. From this point on, the operation of the apparatus to extend the connection to the called station F is identical with that described above, it being understood that in this case the various automatic switches respond to the operation of the impulsing device I38 rather than the impulsing device H0 provided at the station A. Also, the mode of releasing the connection after the conversation is terminated is substantially similar to that described in detail above. In this case, however, the release of the equipment after the calling party hangs up is initiated in response to the restoration of R255 and when the hand set N30 is restored to its cradle to open the switch springs lll l forming a part of the operating circuit for R2553. Wh n R250 restores, it opens, at RA253, a point in the path for applying ground to the control conductor C285, thereby to cause the restoration of Refill and the start relay R499, and opens, at RA252, a point in the holding circuit for R230, causing this relay to restore. The restoration of EH3 results in the interruption of the impulsing circuit to cause the restoration of all of the line relays and their respective associated hold relays. When th line hold relays restore, the various automatic switches are caused to be operated to their respective home positions in the manner pointed out above. If the calling party at the station E is the first to hang up, the automatic switches are restored in the manner described above.

As pointed out in the introductory portion of the specification, one feature of the present invention relates to the arrangement of the apparatus whereby any one of the telephones provided in any one of the sleeping cars may be called from the station located in the club car or from the station located in the dining car, but the equipment in the sleeping car stations can only successfully be operated to extend connections to the dining car station D or to the club car station F. To this end, the relay R2? is provided in the automatic switching appa atus located in the first sleeping car, which relay operates in response to theoperation'of the switch 260 to a predetermined position and, upon operating, functions to short-circuit the impulsing springs of the impulsing device being operated, thereby to render all of the switches non-responsive to any further operation of this impulsing device. With the arrangement shown, this predetermined operating position of the automatic switches succeeds each of the two operating positions corresponding, respectively, tothe dining car station D and the club car station F, and precedes the operating positions respectively corresponding to the several sleeping car stations. More particularly, the fourth oif-normal position of the switch 269 and of the other switches 44! etc., is the predetermined position noted, which fourth off-normal position succeeds the first and second off-normal positions respectively corresponding to the dining car station D and the club car station F and is intermediate the home or first contact position of the switch and the fifth to twenty-fifth off-normal positions of the switch. These latter offnormal positions, or a portion thereof, individually correspond, to the various stations, including the extension stations, provided in the several sleeping cars. one of the sleeping car stations, as, for example, the station A, and the number of a sleeping car station, as, for example, the station C, is dialed at the calling station, the wipers of the several automatic switches are caused to be rotated in the exact manner set forth above until they occupy their respective fourth off-normal positions. Assuming that the call is initiated at the station A, when the wiper 255 is operated into engagement with its associated fifth contact, a circuit is completed for energizing R2), this circuit extending from ground at R0203 by way of RAZM', RA22I, 02M, the switch wiper 265, the fifth contact of the set 262, C2l6, RA23I and through the upper winding of R2) to battery. The relay RZID immediately operates to short-circuit, at RA2l2, the springs I'll of the impulsing device H0, or to complete a bridging path for holding the various line relays operated, whereby further impulses dialed at the station A are prevented from causing any further operation of the several automatic switches. At RAZi l, the relay R246, upon operating, completes a holding circuit for itself, this circuit extending from ground at RA225 by way of PAH I and the lower winding of R2 I 0 to battery. By virtue of this holding circuit, R2 it is maintained energized following the restoration of R200 at the conclusion of the dialing operation, thereby to prevent further actuation of the dialing device from inadvertently causing further operation of the several automatic switches. Since the respective fourth off-normal positions of the respective automatic switches do not correspond to any telephone station but rather are dead, it will be apparent that none of the telephone stations will be signaled following the completion of the dialing operation at the calling station A, and, hence, the calling party will receive no response.

The provision of the call limiting relays corresponding to and including the relay RZI 0 and the circuits in which these relays are involved in no way interferes with the release of the apparatus when the call is cleared out at the calling station. On the contrary, the equipment is released and the various automatic switches restored to normal in the exact manner described above, it being pointed out that the call limiting relays restore If, therefore, a call is initiated at following the restoration of their respective'assoe ciated hold relays. Thus, when R220, embodied in the control equipment associated with the switch 260,-restores, it-opens, at RA225,-the holding circuit for R2I0. Since the operating circuit for the latter relay is previously opened through the restoration of- R200 at the end of the dialing operation, R2! is caused to restore to normal.

With the arrangement'illustrated, no restriction is placedon .the telephone stations D and F in regard to the initiation of calls to the'sleeping car telephone stations. restricting relay corresponding to R2I0 need be included in the switchingv apparatus-located in the club car and illustrated inFig.- 4. v The mode of'operation of the system when a call toone of the sleeping car stations is initiated at the station F is substantially similar=to that just described. In brief, when the hand set 360 is removed from its-supporting cradle, the'hook switch 38!) is operated to its off-normal position to complete, atthe springs/384, a circuit for energizing the lower winding of R420 in serieswith the winding of R490 and to prepare, at the springs 382 and 383, aholdingcircuit for R420. ;-Th e operating circuit for R420 and R490 extendsfrom ground as applied to C392 by way of thesprings 384, C439, the lower winding of R420, C285, RA412 and through the winding of R490 to battery, The relay R420, upon operating, completes, at RA423, its holding circuit, opens, at RA422, a point in the path normally short-circuiting the springs 39I of the impulsing device 390, and completes, at RA424, a path forapplying ground as extended to C439 directly to the'control conductor'C285, thereby to render all of the relays corresponding to R420 noneresponsive to theinitiation of calls 'at their respective associated stations, At RA42 I the relay R420 completes a path for connectingthe receiver and transmitter of the hand set 360 across the talking conductors C284 and C286 of the line 281; Specifically, this path extends from the conductor C284zby way of RA42I', C435, and

the transmitter 365 and the receiver 310 in parallel to the opposite'talking conductor C286.

When R490 operates, it functions, in the manner set forth above, to initiate-the operation ofithe dial tone voltage generator, tocomplete the operating circuit for R463, and to prepare the'-im-.

pulsing circuit over which the various line relays are energized in series with each'other and with R480. In this oase,"the -springs 39I of the impulsing device 390 are arranged to control the impulsing circuit, this circuit" extending from' ground as applied toCI85 by way of CI86, C212,- RA234, the windings of R240, R330, R340, and R350, etc., in series, C436, theimpul'singsprings 39I, C431, the winding of R430, RA464, the Wind ing of R480 and through the resistor 405 to battery. During impulsing, the operation of the several automatic switches conforms exactly to the operation as described above, the operating positions finally 'attainedby these'switches being dependent upon'the number of impulses transmitted from the impulsing device 390; In this connection, it ispointed. out that, if more than ten steps on the part of; each switch are required to reachthe operating position corresponding to the desired called station, two or more digits must necessarily be dialed at the calling station F to cause the switches to be operated to the required operating position. This is true for the reason that impulsing devices of the standard type are incapable of transmitting more than ten impulses for eachactuation of the dial. If it be For this reason, no call."

assumed that .thestationA -is; being called from the station F; the impulsing device 390 will necessarily be actuated to break the impulsing circuit :six times sothat, at the conclusion ofthe dialing operation, the wipers of the switch 260 stand in their respective sixth off-normal posi: tionsq; Shortly following the conclusion of the dialing operation, R200 restores to complete, at

, RA204, a path for connecting the transmitter I65 of theset 262, the switch Wiper 265, C214, R-A22I,

RA20I, RC202 and through the resistor 205 to battery. The resulting-v operation of the signal device I85 gives an audible indication that the station A is being. called; Vifhen the call is answered in the usual manner bylifting the hand 7 set I60 from its cradle, the cradle'switch I80 is operated-to its off-normal positionto interrupt, at the springs I8I and I82, the-above-traced;circuit for energizing the signal device I85. Following this operation, the apparatus is main tained in the'condition described until the connection is cleared out at the calling station F.-

If the call as initiated at the station .35 is in-'- tendedfor the extension station E rather than the station. A, the impulsing device 390 must connecting the transmitting and receiving elements of the handset I00across the conductors of the line circuit. The circuit for energizing the signal device III5 1.isffcomp1eted when R200 restores-and extends. from ground on the jack spring I 53 by waypf t'heplugspring I41, the

winding of the deviceII5, the springs I2I and I22, the springsMI and-I48, 628$. RA254, R0255, the eighth contact of the set 262, the wiper 265,

, C2I4, RAZZLRAZILLRCZM arid.tl'lrollgh the resistor 205 to battery. When the call is answered atflthe station B, this circuit is interrupted through the operation of the cradle switch I20 to open its springs I2I and I221 At the, switch 7 springs I24, a circuit is completed for energizing" R250, this circuit extending from ground at the jack springs I53 by way of the plug spring- I41, the spring I24,-'the plug spring I42, the

jack spring I49, C202 and through the winding ing conductors of the line. This path extends.

from the-talking conductor C284 by way of RA204, C283, the switch wiper 266, the eighth contact of theset 263, C213, the jack and-plug Springs and t ansmitter m5 and t receiver H0 in parallel, the switch springs I2 3 and I22, the plug and jack springs MI and I48;

C2 8I, RA254 and R0256 to the opposite talking conductor C285.

The release of a connection as established to either of the stations A and B on a call initiated at the station F is under the control of the calling party and is substantially similar to that described above with reference to the call initiated at the station A and resulting in a connection to the station F. when the hand set 360 is restored to its cradle after the called party hangs up, the holding circuit for R tZB is interrupted at the springs 382 and 38.3 and the circuit over which the start relay R498 is held operated is interrupted at the springs 384. The resulting operation of R486 followed by the restoration of R463, R485 and R490 causes the common equipment 459 and the automatic switches provided in the respective cars to be restored to normal in the manner described above. The release of the apparatus when the called party at the station A or the station B is the last party to hang up is also similar to that described above with reference to the release of the connection as established between the stations A and F on a call initiated at the station A.

When the call initiated at the station F results in the establishing of a connection to the station B, the apparatus is only completely released when the hand set Mill is returned to its supporting cradle to operate the switch I to its normal position. When this is done, the springs [24 are opened to interrupt the above-traced operating circuit for R2 50 causing this relay to restore. When the hook switch 120 is returned to its normal position, a point is interrupted at the springs I22 and I23 in the path by way of which the elements of the hand set I09 are connected across the talking conductors of the line 281. Thus, this hand set is normally maintained disconnected from the line so that it will not interfere with other connections including the line. The remaining steps in the release of a connection as established to the station B on a call initiated at the station F will be readily apparent from M the preceding description.

While there has been described what is at present considered to be the, preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is contemplated to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

I claim:

1. A telephone system comprising, in combination, a plurality of telephone stations each including an impulsing device and a signal device, automatic switches individually associated with at least a portion of said stations, each of said "switches having operating positions individually 60' corresponding to said stations, means responsive to the initiation of a call at one of said stations for conditioning the switch associated. with a called one of said stations to respond to the operation of the impulsing device at the calling station, means also responsive to the initiation of said call for rendering all of said switches nonresponsive to the operation-of the impulsing devices at the other stations, means responsive to a predetermined operation of the impulsing device at said calling station for causing the switch associated with said called station to operate to the position corresponding to said called station, and means automatically operative following the operationof said last-named, switch to the position corresponding to said called station for can,

ing the operation of the signal device at-said called station.

2. A telephone system comprising, in combination, a plurality of telephone stations each in-' cluding an impulsing device and a signal device, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for conditioning all of said switches to respond to the operation of the impulsing device at the call ing station, means also responsive to the initiation of said call for rendering all of said switches non-responsive to the operation of the impulsing devices at the other stations, means responsive to a predetermined operation of the impulsing device'at said calling station tor'causing each of said switches to operate to the one'position" cor; responding to a called o'ne of said stations, a air-1 cuit for energizing the signal device at said called station, said circuit" being prepared through the operation of the switch at said called station to said one position, and means automatically operative following the operationof said last-named switch to said one position for completing said circuit.

3. A telephone system comprising, in combination, a plurality of telephone stations each'ineluding an impulsing device and'a signal device, automatic switches individually associated with at least a portion of s'aidstations, each ofsaid switches having operating positions individually corresponding to said stations, meansresponsive to the initiation of a call at one of'said stations for conditioning: all of said switches to respond to the operation of the impulsing device at the calling station, means also responsive to the initiation of said call for rendering all of said switches non-responsiveato. the operation of the 'impulsing devices at the other stations, means responsive to a predetermined operation of the impulsing device'at said calling station for causing each oflsaid switches to operate 'toithe one position corresponding to' a called one of said stations, individual circuits for energizing the signal. devices at the respective stations, said circuits being selectively prepared through the operation of said switches and beingsoari'anged that only the circuit for energizing the signal device at said called station is prepared through the operation of said switches to said one posis tion, and means automatically operative following the operation ,of said switches to said one position for completing'the circuit for energizing the signal device at said called station.

1. A telephone system comprising, in combination, a plurality of telephone stations each including an impulsing device, a line interconnecting said stations, automatic; switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initia'tionof a call at one of said stations for conditioning the switch associated with a called one of said stations to respond to the operationof the impulsing device at the calling station, means also responsive to the initiation of said call for rendering allof said switches nonresponsive to the operation of the impulsing devices'at the other stations, and means responsive to a predetermined operation of the impulsing device at said calling station for causing the switch associated with said called station to operate to the-one positioncorresponding to said called station, thereby to prepare a talking loop'between said calling and called substations, said loop being completed when the call is answered at said called station( 5. A telephone system comprising, in combination, a plurality of telephone stations each including an impulsing device, a line interconnecting said stations, automatic switches individually associated with each ofsaid stations, each of said said call for rendering'all of said switches non responsive to the operation of the impulsing devices at the other stations, means responsive to a predetermined operation of the impulsing device associated with said calling station for causing the 'switchat said called stationrto operate to the one position corresponding to said called station, thereby to prepare a talking loop between said calling and called stations, and means automatically operative following the operation of said last-named switch to said one position for further preparing said loop, said loop being completed when the call is answered at said called station.

6. A telephonesystem comprising. in combination, a plurality of'stations each including a tele phone and an; impulsing device, a line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stationsfor-connecting the telephone at the calling station across the talking conductors of said line and for conditioning all of said switches to respond to the operation of the impulsing device at said calling station, means also responsive to the initiationof said call for preventing the telephones at the other stations from being connected across said talking conductors in response tothe initiation of calls at the corresponding stations and for rendering said switches non-responsive to the operation of, the impulsing devices at said other stations, means responsive to a predetermined operation of the impulsing device at said calling station for causing said switches to operate to the one position corresponding to a called one of said stations, and a path for connecting the telephone at the called station across said talking conductors, said path being at least partially completed when the switch at said called station is operated to its said one position. I

"I. A telephone system comprising, in combination. a plurality of stations each including a telephone and an impulsing device, a line interconnecting said stations and including a pair of talk-. ing conductors, automatic switches individually associated with at least a portion of'said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to'the initiation of a call at one of said stations for connecting the telephone at the calling station across'the talking conductors of said line and for conditioning all of said switches to respond to the operation of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stations andfor rendering said switches non-responsive to the operation of the'impulsing devices at said other stations, means responsive to a predetermined operation of the impulsing device at said calling station for causing said switches to operate to the one position corresponding to a called one of said stations, a path for connecting the telephone at the called station across said talking conductors, said path being partially completed when the switch at said called station is operated to its said one position, and means automatically operative following the operation of said lastnamed switchto its said one position for completing said path.

8. A telephone system comprising, in combination, a plurality of stations each including a telephone and an impulsing device, a line interconnecting said stations and including a pair of talking conductors, automatic switches individu- 1ally' associated with at least a portion of said stations, each of saidswitches having operating positions individually corresponding tosaid stations, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across the talkingconductors of said line and for conditioning all of saidswitches to respond to the operation of the impulsingdevice at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other the corresponding stations and for rendering said switches non-responsive to the operation of the impulsing devices at said other stations, means responsive to a predetermined operation of the impulsing device at said calling station for causing said switches to operate to the one position corresponding to a called one of'said stations, and circuit connections controlled by said switches for selectively connecting the respective telephones across said talking conductors independently of said second-named means, said circuit connections being so arranged that onlythe telephone at said called station is connected across said talking conductors in response to-the operation of said switches to said one position.

"9. A telephone system comprising, in combina tion, a plurality of telephone stations each including'an impulsing device and a signal device, a. line interconnecting said stations, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for preparing a talking loop between the calling station and a called station, said talking. loop including said line, means responsive to the initiation of said call for conditioning the switch associated with the called station to respond to the operation of the impulsing device at said calling station, means also responsive to the ini tiation of said call for rendering said switches non-responsive to the operation of the impulsing devices at the other stations, means responsive to a predetermined operation of the impulsing device at said calling station for causing the automatically operative following the operation of said last-named switch to said one position for causing the operation of the signal device at said called station and for extending said talking loop to said called'station.

10. A telephone system comprising, in combination, a plurality of stations each including a telephone, an impulsing device and a signal device, a line interconnecting said stations and including a pair of talkingconductors,automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conductors and for conditioning all of said switches to respond to the opera tion of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones atthe other stations'from being connected across said talking conductors in response to the initiation of calls at the corresponding stations and for rendering said switches non-responsive to the operation of the impulsing devices at said other stations, means responsive to a predetermined operation of theimpulsing device at said calling station for causing said switches to operate to the one position corresponding to acalled one of said stations, a path for connecting the telephone at the called station across said talking conductors, said path being partially completed when the. switch at said called station is operated to its said one position, and means automatically operative following the operation of said switches to said one position for completing said path and for causing the operationof the signal device at said call d station.

11. A telephone system comprising in combination, a plurality of stations each including a telephone. an impulsing device and a signal de-' vice, a line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conductors and for conditionin all of said switches to respond to the operation of the im ulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stations and for rendering said switches non-responsive to the operation of the impulsing devices at said other stations, responsive to a predetermined operation of the impulsing device at said calling station for causing said switches to operate to the one position corresponding to a called one of said stations, individual circuits for energizing the signal devices at the respective stations, said circuits being selectively prepared through the operation of said switches and being so arranged that only the signal device at said called station is energized in response to the operation of said switches to said one position, and circuitconnections controlled by said switches for'selectively connecting the respective telephones across said talking conductors independently of said second-named means, said circuit connections being so arranged that only the telephone at said called station is connected across said talking conductors in response tothe operationof said switches to said one position.

12. A telephone system comprising, in combination, a plurality of stations each includinga telephone, an impulsing device and asignal device, a line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually corre sponding to said stations, an undulating voltage generator connected to impress its output voltage between said talking conductors, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conductors and for initiating the operation of said generator, whereby an audible indication is given to the calling party that said line is idle, means responsive to the initiation of said call for conditioning all of said switches to respond to the operation of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stations and for rendering said switches non-responsive to the opera,- tion of the impulsing devices at said other stations, means responsive to a predetermined operation of the impulsing-device at said calling station for arresting the operation of said generator and for causing said switches to operate to the one position corresponding to a called one of said stations, a path for connecting the telephone at the-called station across said talking conductors, said pathbeing partially completed when the switch at said called station is operated to its said one position, and means automatically operative following the operation of said switches to said one position for completing said path and for causing the operation of the signal device at said called station.

13. A telephone system comprising, in combination, a plurality of stations each including a telephone, an impulsing device and a signal device, a line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least a portion of said stations, each of said switches having operating positions individually correspending to saidstations, an undulating voltage generator connected to impress its output voltage between said talking conductors, means responsive to the initiation of a call at oneof said stations for connecting the telephone at the calling station across said talking conductors and for initiating the operation of said generator, whereby an audible indication is given to the calling party that said line is idle, means responsive'to the initiation of said call for conditioning all of said switches to respond to the operation of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stations and for rendering said switches non-responsive to the operation of the impulsing devices at said other stations, means responsive to a predetermined operation of the impulsing device at said calling station for arresting the operation of said generator and for causing said switches to operate to the one position corresponding to a called one of said stations, individual circuits-for energizing the signal devices at the respective stations, said circuits being selectively prepared through the operation of said switches and beingso arranged 5 that only the signal device at said called station is energized in response to, the operation of 's'aidswitches to said one position, and'circuit connections controlled by said switches forsel'ectively 14. A telephone system comprising in.combination, a plurality of stations? each including a telephone, an impulsing device and a: signal device, a line interconnecting said stations and including a pair of talking conductors, automatic Switches individually associated with at least a portion of said stations, each of said switches having a predetermined operatin position and a plurality of additional operating positions indig5 vidually correspondin to said stations, means responsive to the initiation of a' call at one of said stations for connecting the telephone at the calling station across said talkingconductors and for conditioning all of said switches to respond to -3 the operation of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to theinitiafor rendering said switches non-responsive'to the operation of the impulsing devices at said other other stations areprevented, means responsive to a different predetermined operation of the impulsing device at said calling station for causing 50 said switches to operate to the one position correfor connecting the telephone ,at the called sta: tion across said talking conductors, said path being partially completed when the switch at said called station is operated to its said one position, and means automatically operative following the operation of said switches to said one position for completing said path and for causing the opera-5 tion of the signal device at said called station. 60 15. A telephone system comprising, in combination, a plurality of stations each including a telephone, an impulsing device and .a signal device, a line interconnecting said stations and including a pair of talking conductors, automatic 65 switches individually associated with at least a portion of said stations, each of said switches having a predetermined operating position and a plurality of additional operating. positions in dividually corresponding to said stations, means 70 responsive to the initiationof a call at one of said stations for connecting the. telephone at the calling station across said talking conductors and for'conditioning all of said switches to respond to the operation of the impulsing device 75 at said calling station, means alsoresponsiveto tion of calls at the correspondingstations and impulsing devices at said other stations, means sponding to a called one of said stations, a path the, initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors, in response. ,to the initiation of calls at the corresponding stations and for rendering I said :5

switches non-responsive to the operation ofthe irnpulsing'devices at said other stations, means responsive to impulses transmitted from the impulsing device at saidcalling station for causing said switches to operate to the one position corresponding to a called one of said stations or to said predetermined position depending upon the'numberof impulses transmitted from the impulsing, device at said calling station, a path for, connecting the telephone at the called 15 station across said talking conductorsfa circuit for energizing the signal device at said calling station, said path and said circuit only being completed in response to the operation of the switch associated with said called station to its said one position, and means responsive to the operation of one of said switches to said predetermined position for rendering said switches non-responsive to further impulses transmitted from said calling station, whereby-calls 'from said calling station to" certain of the otherstations are prevented.

'16. A telephone system comprising, incombination, a plurality of stations each including a telephone, an impulsing device and a signal device, a line interconnecting said stations and including a pair of talkingconductors, automatic switches individually associated with at least a portion of said stations, each of said switches having a predetermined operating position and a plurality of. additional operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conduc tors and for conditioning all of said switches to respond-to the operation or the impulsing device atsaid callingstation,"means also responsive to the initiation of said call forpreventing the telephones at the other. stations from being connected across said talking conductors in respons'e to the initiation of calls at the corresponding stations and for rendering said switches non-responsive to the operation of the responsive to impulsestransmitted from the impulsing device atsaid calling station ior causing said switches to operate to the one position corresponding to a called one of said stations orv to said predetermined position depending upon the number of impulses transmitted from the impulsing device at said calling 'statiomindividual circuits for-energizing the, signal devices at the respective stations, said circuits being selectively prepared through the operation of-said switches and being so arranged that only the signal device at said called station is energized response to the operation of said switches to said one position, and; means responsive to the operation of one of said switches to said predeter mined position for rendering said switches nonresponsive tofurther impulses transmitted from said calling station, whereby calls from said calling station to certain of the other stations are prevented.

17. A telephone system comprising, in combination, a plurality of stations each including a telephone, an impulsing device. and a signal device, a'line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least a portion of said stations, each of said switches having a predetermined operating position and a plurality of additional oeprating positions individually corresponding to'said stations,

an undulating voltage generator connected to impress its output voltage between said talking conductors, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conductors and for initiating the operation of said generator, whereby an audible indication is given to the calling party that said line is idle, means responsive to the initiation of said call for conditioning fall 'of said switches to respond to the operation of the impulsing device at said calling station, means also responsive to the initiation of said call for preventing the telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stations and for rendering said switchesnon responsive to the operation of the impulsing devices at said other stations, means responsive to impulses transmitted from the impulsing device at said calling station for arresting the operation of said genera-tor and for causing said switches to operate to the one position corresponding to a called one of said stations or to said predetermined position depending upon the number of impulses transmitted from the imergizing the signal device at said called station,

said path and said circuit only being completed in response to the operation of the switch associated with said called station to its said one position, and means responsive to the operation of one of said switches to said predetermined position for rendering said switches non-responsive to'further impulses transmitted from said calling station, whereby calls from said calling'station to certain of the other stationsare prevented.

18. A telephone system comprising, in combina-' tion, a plurality of stations each including a telephone, an impulsing device and a signal device, a line interconnecting said stations and including a pair of talking conductors, automatic switches individually associated with at least-a portion of said stations, each of said switches having a predetermined operating position and a plurality of additional operating positions individually corresponding to said stations, an undulating voltage generator connected to impress its output voltage betweensaid talking conductors, means responsive to the initiation of a call at one of said stations for connecting the telephone at the calling station across said talking conductors and for initiating the operation of said generator, whereby an audible indication is given to the calling party that said line is idle,

means responsive tothe initiation of said callior conditioning allof said switches to respond to the operation of the-impulsing device at said calling station, means also responsive to the initiation of said call -for preventing the -telephones at the other stations from being connected across said talking conductors in response to the initiation of calls at the corresponding stationsfandfor rendering said switches nonresponsiveto'the operation of the impulsing devices at said other stations, means responsive to impulses transmitted from the impulsing device at said calling station for causing said switches to operate to the one position corre sponding to a called one of said stations or to said predetermined position depending upon the number of impulses transmitted from the im pulsing device at said calling station, a path for connecting'the telephone at the called station across said talking conductors, a circuit for energizingthe signal device at said called station, said pathand said circuit being prepared whenthe switch associated'with said called station is operated to its said one position, means automatically operative following the operation of said last-named switch to said one position for completing said path and said circuit, and means responsive'to the operation of one of said switches to said predetermined position for rendering said switches non-responsive to further impulses transmitted from said calling station, whereby calls fromsaid calling station to certain of the other stations are prevented.

19. In a telephone system, a pair of stations each including a telephone and animpulsing device, a line extending between said stations and including a pair of talking conductors, an impulse responsive switch associated with one of said stations and operative to a position corresponding; to the other, of said stations, an undulating voltage generator connected-to impress its output voltage between said talking conduc-- tors, means responsive to the initiation of a call at the other of said stations for connecting the telephone 'thereat across said talking conductors and for initiating the operation of said generator, whereby'the calling party is given an audible indication that said line is idle, means also responsive to the initiation of said'call for conditioning said switch to respond to the operation of the impulsing device at the calling station, and means responsive to the operation of the impulsing deviceat the calling station for arresting the operation of said generator.

20. Ina telephone system, a pair of stations each including a telephone and an impulsing device, a line extending between said stations and including a pair of talking conductors, an impulse responsive switch associated with one of said stations and operative to a position corresponding to the other of said stations, an undulating voltage generator connected to impress its output voltage between said talking conductors, means responsive to the initiation of acall at the'other of said stations for connecting the telephone thereat across said talking conductors and for initiating the operation of said generator, whereby the calling party is given an audible indicationthat said line is idle, means also responsive tothe initiation of said call for conditioning said switch to respond to impulses transmitted thereto'from the impulsing device at the calling station, and means responsive to the first pulse transmitted from the impulsing device at said calling station-for arresting the operation of said gene'rator.

21. In a telephone system, a station including a telephone andan impulsing device, said telephone including a receiver, a station selecting impulse responsiveswitch associated with said station, an undulating voltage generator, a circuit for energizing said receiver from said-generator, means responsive to the initiation of a call at said station for completing said circuit and for initiating the operation of said genera tor, means also responsive to the initiation of a call at said station for conditioning said switch to respond to the operation of said impulsing device, and means responsive to the operation of said impulsing device for arresting the operation of said generator.

22. In a telephone system, a station including a telephone and an impulsing device, said telephone including a receiver, a station. selecting impulse responsive switch associated with said station, an undulating voltage generator, a circuit for energizing said receiver from said generator, means responsive to the initiation of a call at said station for completing said circuit and for initiating the operation of said generator, means also responsive to the initiation of said call for conditioning said switch to respond to impulses transmitted thereto from said impulsing device, and means responsive to-the first pulse transmitted from said impulsing device for arresting the operation of said-generator.

23. In a telephone system, a station including a telephone and an impulsing device, said telephone including, areceiver, a station selecting impulse responsive switch associated with said -station, an undulating voltage generator, a circuit for energizing said receiver from said generator, a relay operative to initiate the operation of said generator, an operating circuit for said relay, a pair of relays operative in response to the initiation of a call at said station, one of said pair of relays being-operative to complete said first-named circuit and to condition said switch to respond to impulses transmitted from ing of said first-named relay, said path being completed in response to the restoration of said first-named relay.

24. A telephone system comprisingin combination, a plurality of stations, a line interconnecting said stations, a relay associated with each of said stations, impulse responsive station selecting apparatus individually associated with said stations, each of said relays being operative to condition the associated station selecting apparatus to respond to impulses-transmitted thereto from the corresponding station so long as said line is idle, and means controlled by each of said operating.

25. A telephone system comprising, in combination, a plurality of stations, a line interconrelays for preventing all of the other relays from necting said stations, said line including a con-- trolconductor, a'relay associated with each of said stations, impulse responsive station selecting apparatus individually associated with said stations, each of said relays being operative to condition the associated station selecting apparatus to respond to impulses transmitted thereto from the corresponding station only when a predetermined potential is present on said control conductor, and means controlled by each of said relays for removing said predetermined potential from said. control conductors.

26. A telephone system comprising, in combination, a plurality of stations each including an impulsing device,-a line interconnecting said sta-z tions, an automatic swq'tch associated with each of said stations, each of said switches having a predetermined operating position and a plurality of additional operating positions individually cor,-. responding to said stations, means responsive to the initiation of a call at one of said stations for conditioning said switches to respond to impulses transmitted from the impulsing device at the calling station,,means responsive toimpulses transmitted from the impulsing device at the calling station for causing said switches tooperate to the position corresponding to a'called one of said stations or to said predetermined position de-, pending upon the number of impulses transmitted iromthe impulsing device'at said-calling sta tion, and means responsive to the operation of one of said switches to said predetermined position for rendering said switches non-responsive to further impulses transmitted from the said impulsing deviceat said calling substation, where-' bycalls from saidcalling station to certain of the other stations are prevented.

2'7. A telephone system comprising, in combination, a plurality of stations each including an impulsing device, a line interconnecting said stations, an automatic switch associated with each of said stations, each of said switches having a home positioma plurality of operating positions individually corresponding to said stations and a predetermined operating position intermediate said home position and certain of said plurality of operating positions, means responsive: tothe ditioning said switches to respond to impulses transmitted from the impulsing'device at-the calling station, -means responsive to impulses transmitted from the impulsing device at the 28. Atelephone system comprising, in combi-' nation, a plurality of stations each including an impulsing device, a line interconnecting said stations, an automatic switch associated with each of said stations; each of said switches having a predetermined operating position and a plurality of additional operating positions individually corresponding to said stations, means responsive to the initiation of a call at one of said stations for conditioning said switches to respond to impulses transmitted from the impulsing device at the calling station, means responsive to impulses transmitted from the impulsing device at the calling station for causing said switches to operatev to the position corresponding to a called one of said stations or tosaid predetermined position dependinitiation of a call at one of said stations for con..

ing upon the number of impulses transmitted from the impulsing device at said calling station, a relay operative to short-circuit. the impulsing device at said calling station thereby to render said switches non-responsive to further operation thereof, and an operating circuit for said relay, said circuit being completed upon the operation of the switch associated with said calling station to said predetermined position, whereby calls from said calling station to certain of the other stations are prevented.

29. A telephone system comprising, incombination, a plurality of stations each including an impulsing device, a line interconnecting said stations, an automatic switch associated with each of said stations, each of said switches having a home position, a plurality of operating positions individually corresponding to said stations and a predetermined operating position intermediate said home position and certain of said plurality of operating positions, means responsive to the initiation of a call at one of said stations for conditioning said switches to respond to impulses transmitted from the impulsing device at the calling station, means responsive to impulses transmitted from the impulsing device at the calling station for causing said switches to operate to said predetermined position or to one of said operating positions intermediate said home position and said predetermined position depending upon the number of impulses transmitted from the impulsing device at said calling station, a relay operative to short-circuit the impulsing device at said calling station thereby to render said switches non-responsive to further operation thereof, and an operating circuit for said relay, said circuit being completed upon the operation of the switch associated with said calling station to said predetermined position, whereby calls from said calling station to certain of the otherstations are prevented.

30. A telephone system comprising, in 001111911,

nation, a plurality of stations each including a telephone and an impulsing device, a line interconnecting said stations, automatic switches individually associated with said stations, each of said switches including a pulsing relay and having a plurality of operating positions individually corresponding to said stations, a normally incomplete pulsing circuit serially including said pulsing relays, means operative in response to the initiation of a call at one of said stations for connecting the telephone at the calling station to said line and for serially including the impulsing device at said calling station in said pulsing circuit, means also operative in response to the initiation of said call for completing said pulsing circuit, means including said pulsing relays operative in response to operation of the impulsing device at said calling station to interrupt said circuit for causing all of said switches to operate to the one position corresponding to a called one of said stations, and means comprising the switch associated with said called station for connecting the telephone at said called station to said line.

31. A telephone system comprising, in combination, a plurality of stations each including a telephone and an impulsing device, a line interconnecting said stations, automatic switches individually associated with said stations, each of said switches including a pulsing relay and having a normal position and a plurality of operating positions individually corresponding to said stations, a normally incomplete pulsing circuit serially including said pulsing relays, means operative in response to the initiation of a call at one of said stations for connecting the telephone at the calling station to said line and for serially including the impulsing device at said calling station in said pulsing circuit, means also operative'in response to the initiation of said call for completing said pulsing circuit, means including said pulsing relays operative in response to operation of the impulsing device at said calling station to interrupt said circuit for causing all or said switches to operate to the one position corre: sponding to a called one of said stations, means comprising the switch associated withsaid called station for connecting the telephone at said called station to said line, means responsive to a release operation performed at said calling station for interrupting said pulsing circuit, thereby to cause said switches to be restored-to normal, and 'means for maintaining said pulsing circuit interrupted for a predetermined time interval after said re,- lease operation is performed, thereby to insure the restoration of said switches to normal even though asecond call is waiting. J

32. A telephone system comprising, in combi nation, a plurality of stations each includinga telephone and an'impulsing device, a line inter: connecting said stations, automatic switches individually associated with said stations, each of said switches including a pulsing relay and hav ing a plurality of operating positions individually corresponding to said stations, a normally incomplete pulsing circuit serially including said pulsing ing the telephone at the calling station to said line and for serially including the impulsing device at said calling station in said pulsing circuit,

means also operative in response to the initiation of said call for preventing the telephone atthe other stations from being connected to said line in response to calls initiated at the corresponding stations'and for preventingv the impulsing devices at said otherstations from being serially included in said pulsing circuit, means also operative-in response to the initiation of said call for complet ing said pulsing circuit, means including said pulsing relays operative in response to operation of theim-pulsing device at said calling station to interrupt said circuit for causing all of said switches to operate to the one position corresponding to a called one of said stations, and means comprising the switch associated with said cal-led station for connecting the telephone at said called station to said line.

3 3. A telephone system comprising, in combination, a plurality of stations each including a telephone and an impulsing device, a line interconnecting said stations, automatic switches individually associated with said stations,v each of said switchesincluding a pulsing relay and having a normal position and a plurality of operating positions individually corresponding to said stations, a normally incomplete pulsing circuit serially including said pulsing relays, means operative in response to the initiation of a call at one of said stationsfor connecting the telephone at the calling station to said line and for serially including the impulsing device at said calling station in said pulsing circuit, means also operative in response to the initiation of said call for preventing the telephones at the other stations from being connected to said line in response to calls initiated at the corresponding stations and for preventing the impulsing devicesv at said other stations from being serially included in said pulsing circuit, means also operative in response to the initiation of said call for completing said pulsing circuit, means in-- cluding said pulsing relays operative in response 

